Grinding tool for lenses



Dec. 3, 1963 R. E. MIDDLETON ETAL GRINDING TOOL FOR LENSES Filed Oct.27, 1960 IN V EN TOR. ROBERT E MIDDLETON CLIFFORD yRlsTopr-lmsolv BY ATTORNEY United States Patent 3,112,585 GRINDING TOOL FOR LENSES RobertE. Middleton and Clifford C. Christopherson, Denver, (1010., assignorsto Superior Visual Products (30., Denver, Colo., a partnership FiledGet. 27, 1960, Ser. No. 65,317 6 Claims. (Cl. 51-204) The presentinvention relates to an attachment to be used in grinding lenses and thelike. More particularly, this invention relates to an attachmentconstructed in such a fashion as to retain a number of differentgrinding inserts, and which is especially adapted to grind a wide rangeof curvatures for contact lenses.

Contact lenses in use today are generally small and relatively thin, sothat a relatively small change in curvature of the lens necessitates aconsiderable prescription change. It is therefore highly desirable toincorporate into a single member a number of grinding surfaces which areeach of a different radius of curvature and are easily interchangeablefor grinding varying contact lens prescriptions. Moreover, a single toolor member is advantageous in special grinding situations such as wherethe lens must be ground progressively, requiring several grindingsurfaces each of a different radius of curvature to complete thegrinding operation. In this and other applications the present inventionovercomes the need for numerous tools by providing a universal typeattachment which may be formed in a unique way to make possible a safe,rapid and efiicient means for grinding curvatures into lenses and thelike over a wide range of radius sizes and configurations.

Accordingly, it is a principal object of the invention to provide foruse in association with a lens grinding machine, a universal type toolfor grinding varying configurations and curvatures in lenses and thelike.

It is another object of the invention to provide, in a lens grindingmachine, a tool so constructed that its position atop a motor drivespindle can be selectively varied, to successively present grindingmembers of different configurations in grinding position.

t is a further object of the invention to provide a grinding orpolishing tool presenting a number of surfaces of selected curvaturesfor grinding or polishing lenses of different sizes and curvatures.

It is a further object of the invention to provide, for use inassociation with a lens grinding machine, an attachment having aplurality of grinding members arranged to permit successive positioningfor rotation about the axis of rotation of the machine to presentgrinding surfaces of different curvatures for contact lenses and thelike.

It is a still further object of the invention to provide a universaltype holder for grinding members which is simple in construction, has along service life, and is easily used in a lens grinding machine.

The above and other objects and advantages of the present invention willbecome more apparent from the following detailed description takentogether with the accompanying drawings, in which:

FIGURE 1 is a front view of a preferred form of the invention, as usedin association with a lens grinding machine; and

FIGURE 2 is a sectional view of the preferred embodiment, showing agrinding insert in attached relation.

3,112,585 Patented Dec. 3, 1963 "ice Referring more particularly to thedrawings, there is shown by way of illustrative example a preferred formof grinding tool defined by a generally spherical body 12. Essentially,the body 12 is formed to accommodate in a unique way a maximum number ofgrinding membeds defined by inserts 13 for mounting in association witha lens grinding machine 14. For purposes of description the lensgrinding machine is representative of various drive means which may beemployed and is made up essentially of a motor drive spindle 16 rotatedby a motor drive unit 17, the spindle projecting upwardly through agenerally cylindrical storage hopper 18 which is open at the top forreception of the body member 12.

Specifically, the body portion 12 is designed for use such that eachgrinding member 13 may be selectively and successively positioned inalignment with the drive spindie for rotation about its axis so as topresent a surface of the desired radius of curvature for grinding of aparticular lens prescription. Accordingly, for each grinding memberthere must be provided a diametrically-opposed, aligned attaching meansfor disposition of the grinding tool on the drive spindle with thegrinding member in diametrically-opposed relation thereto. To this end,the grinding tool is made preferably of a spherical shape having aseries of bores 20 with a diametricallyopposed, coaxially aligned recessor receptacle 22 corresponding to each bore to receive a grinding member13. Furthermore, although not an essential part of this invention, thebores 20 are so staggered in relation to one another as to permitalternate disposition of the recesses 22 between the bores undersubstantially uniform spacing so as not to Weaken the body portion as awhole while providing the maximum nurnber of aligned bores and recessesfor each grinding member. In this connection, no set geometricconfiguration need be employed and the spacing between bores andreceptacles may be dictated in accordance with the number of grindinginserts desirably secured within the spherical body portion, and ofcourse the size of the body may be varied also in accordance with thedesired number of grinding members to be positioned therein.

In design and construction, each bore and recess is positioned on aradial line extending from the center of the body, each bore beingessentially of the same size, diameter and length so as to provide forsnug-fitting disposition atop the motor drive spindle 16 in order thatno slippage between the spindle and the body portion will occur duringrotation. The receptacles 22 may be in the form of relatively shallow,wide, circular openings 24 to provide a broad base of the desired sizefor disposition of each grinding member 13, and in this connection eachreceptacle may be of a varying cross diameter in order to accommodategrinding inserts of different sizes. Adjacent the exterior of the bodyeach opening 24 di verges outwardly to form a relatively broad beveledsurface 25 for ease of insertion of the grinding members 13 and toinsure that no contact will be made with the edges of the lens duringgrinding.

In accordance with the preferred'form of invention, each grinding member13 is in the form of a generally cylindrical insert having a convex,outer, curved surface 28 which is formed on a radius of curvature inaccordance with a particular, selected lens prescription. Thus eachcurved surface 28 will vary in radius, size and configuration inaccordance with the particular size and radius of curvature for a lensto be ground. Although each insert may be merely mounted in snug-fitrelation within each of the respective openings 24, it is mostpreferably permanently positioned in each respective opening through theuse of a suitable adhesive and thereby forms essentially a unitary partof the spherical body portion. In accord with conventional practice, afelt pad 31 may be secured over the outer curved surface 28 of eachinsert so as to provide the actual grinding surface for the contactlens. Actually, the felt pad 39 forms a relatively broad curved surfacewithin the beveled portion of the receptacle and together with theinsert itself provides a relatively large curved surface area within thebeveled portion to allow ample clearance between the edges of theopening and the contact lens during grinding and thus prevent any dangerof damage to the edges of the lens.

In forming the body portion and grinding member, the body portion 12 ispreferably composed of glass or a tough, horny plastic substance, whichis desirably made transparent or of a clear color. In turn, each of thegrinding inserts may be of either a plastic or metallic material whichpresents a hardened curved surface in forming the outer curved end 28thereof, although of course little or no wear will be associated withthe surface of the insert proper in that the felt pad will remain incontact with the contact lens throughout the grinding operation.

In operation, each grinding insert is placed in position for use byfitting its aligned bore over the motor drive spindle 16. A suitableabrasive or polishing agent may be applied to the grinding surfaceformed by the felt pad so that upon rotation of the grinding tool, alens may be brought into contact with the abrasive surface to form thedesired radius of curvature in the lens. Normally, only one insert isnecessary for each particular lens correction although as stated aparticular radius of curvature may be accomplished through a series ofprogressive grinding operations using inserts of progressivelydecreasing radius. In this instance, or generally when desired to changegrinding surfaces, the tool may be rapidly and easily removed from thespindle and then replaced so that a dilferent bore and aligned insert ispositioned in grinding position for the next operation, and this may bedone without stopping the motor. In this way, the lens may undergo asmany grinding operations as is found necessary to be brought to thedesired end configuration, and in this relation the grinding inserts maybe used in both grinding and polishing operations, and may be used inthe formation of peripheral curves, or beveled surfaces, along with themajor curvatures.

Any excess abrasive material will simply fall into the storage hopper 18in the course of the grinding operation. Moreover, the abrasive materialcollected in the storage hopper may be separated from the particlesground off the lens and reused as desired.

Essentially, therefore, the present invention comprises a series ofaligned grinding members 13 and securing means 20 for attachment of eachrespective grinding member in grinding position in association with alens grinding machine. An especially compact relation is provided wherethe diametrically-opposed and aligned grinding members and securingmeans are disposed to radiate from a common center, and it is consideredto be particularly novel and effective to construct the respectivegrinding members and securing means in the form of diametricallyopposedrecesses for reception of grinding inserts and bores, respectively, in acommon body portion. In this connection, it will be evident thatalthough the body portion 12 is preferably of a generally sphericalconfiguration, other geometric forms may be adopted such as arectangular or oval form. However, the generally spheri: cal formprovides for the most compact arrangement in a common unit for all thegrinding inserts and additionally provides the safest means of formingsuch an attachment where the member is under constant rotation andrequires periodic removal and replacement.

As a further possible modification it will be recognized that althoughthe grinding members are in the form of inserts, they may formprojections from the surface of the body or may be formed out of thespherical body portion itself merely by countersinking into the bodyportion at spaced intervals to provide a generally convex area fordisposition of the felt pad. Additionally, the inserts may be formed forgrinding or polishing concave as well as convex surfaces. Again, the useof inserts provides for separate, accurate formation thereof followed byeither press fitting disposition or adhesive attachment into thereceptacles. Either way, by the use of inserts, it is possible toreplace them as desired without destruction of the entire body.

From the foregoing, it will be evident that various modifications andchanges may be resorted to in the grinding tool of the present inventionwithout departing from the scope thereof as defined by the appendedclaims.

What is claimed is:

l. A grinding and polishing tool for use in association with agrindingand polishing machine and the like comprising a body having aplurality of pairs of opposed bores and recesses, said bores beingshaped for connection to the machine, and grinding inserts each having aspherical surface and positioned within said recesses with the sphericalsurface outward, each surface having a different radius of curvature forgrinding a selected lens, the axis or" the bore of each of said pairsbeing aligned with the axis of the spherical surface of the insertpositioned within the bores corresponding recess.

2. An attachment for a grinding and polishing machine and the likeconsisting of a generally spherical body, and a series of coaxially alined, radially extending bores and spaced apart circular recesses in saidbody, a grinding insert retained Within each recess, said grinding andpolishing insert having a body portion and a grinding surface, eachsurface portion being generally convex and of a selected configurationfor grinding a selected curvature in a lens.

3. A grinding and polishing tool for use in association with a'grindingand polishing machine having a rotary drive spindle thereon, said toolconsisting of a body, a series of relatively shallow radial recessesdisposed in spaced relation about said body, a series of radial borescorresponding in number to the radial recesses and being d1sposed inspaced relation about said body between the radial recesses with eachbore being diametrically opposed to and coaxially aligned with a radialrecess for reception of the drive spindle therein, and a grinding insertpositioned in each radial recess having a generally convex outwardlydisposed grinding surface whereupon positioning of the drive spindle ina bore, a grinding surface 1s positioned for rotation about the axis ofrotation of the drive spindle for the grinding of a selected curvatureinto a contact lens.

4. A grinding and polishing tool according to claim 3 wherein eachradial recess is formed of an inwardly disposed circular opening forreception of each grinding insert and an outwardly flared beveledsurface at the surface of said body, each grinding insert beingdimensioned for disposition in a corresponding opening with itsgenerally convex grinding surface coextensive with the beveled surfaceof each radial recess.

5. A grinding tool for use in association with a rotary drive lensgrinding machine in the grinding of contact lenses and the like,comprising a series of spaced grinding members presenting sphericallyshaped grinding surfaces each of a different radius of curvature, saidgrinding members being arranged in peripheral spaced relation on aspherical surface about a common center, and a corresponding series ofdiametrically-opposed securing means axially aligned with the sphericalaxis of each respective grinding member to provide for connection to thelens is adapted for connection to be rotated by the machine grindingmachine. for successively positioning each grinding surface at the 6. Agrinding tool for use in association with a grinding axis of rotationfor a grinding operation.

machine for rotation thereby in the grinding of a selected curvatureinto contact lenses and the like comprising, 5 Rfel'mces Cited 111 thefile of this P a series of axially aligned diametrically-opposedsecuring UN D S AT PATENTS 5: g gg e 231 ififiji 22 w i t d my 26 1910having an outer curved ge iie rally co nve x end gort on de 1973527 DiSam) Sept 1934 2,395,700 Walker Feb. 26, 1946 fining a grinding surfacewhereupon each securing means 10 3 034 267 Feeney May 15 1962

1. A GRINDING AND POLISHING TOOL FOR USE IN ASSOCIATION WITH A GRINDINGAND POLISHING MACHINE AND THE LIKE COMPRISING A BODY HAVING A PLURALITYOF PAIRS OF OPPOSED BORES AND RECESSES, SAID BORES BEING SHAPED FORCONNECTION TO THE MACHINE, AND GRINDING INSERTS EACH HAVING A SPHERICALSURFACE AND POSITIONED WITHIN SAID RECESSES WITH THE SPHERICAL SURFACEOUTWARD, EACH SURFACE HAVING A DIFFERENT RADIUS OF CURVATURE FORGRINDING A SELECTED LENS, THE AXIS OF THE BORE OF EACH OF SAID PAIRSBEING ALIGNED WITH THE AXIS OF THE SPHERICAL SURFACE OF THE INSERTPOSITIONED WITHIN THE BORE''S CORRESPONDING RECESS.